How do metal seats and bodies work together? Dissimilar metals

[ChEMatt]

Just wondering out loud, I'm working on sizing some PSVs and I got to wondering how you have a stainless steel seat but a carbon steel body without having some sort of galvanic corrosion going on? Forgive the very newbie question. Is there some sort of layer between the two that prevents the corrosion? Is there a general type of metal that is used for that? I'm just wondering; it's a topic I obviously know little about!

(Hopefully this is the right forum for this question. If not, please suggest where this should have gone?)

Thanks!

-Matt

 

[EdStainless]

1. If you are using a CS body then it isn't a severe environment.
2. Where the seat mates to the body is very thick and a little surface corrosion is no big deal.

You could post either here or the corrosion engineering forum, most of us that read one also read the other.

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P.E. Metallurgy, Plymouth Tube

 

[metengr]

For galvanic corrosion the surface area of the carbon steel (anode) to stainless (cathode) plays a major role. Large anode to cathode surface area works best.